The licenses for the Deluxe Edition content are tied to your Xbox account, and will only be accessible on Xbox. If you set up cross save so that you can use your Xbox account through Steam, you will not have access to the Beyond Light content on Steam, and the Deluxe Edition items like the Sparrow, Ghost, and No Time To Explain will only be usable if you equip them while on Xbox. If you unequip those items, you will not be able to equip them again while on Steam, but will have to sign in on your Xbox to equip them.